1. Field of the Invention
The present invention generally relates to wire cutters that are specifically designed to cut wire and strip the insulation from wire. The present invention also relates to circuit testing probes of the type that test for electricity flowing through a wire by extending a piercing probe through the insulation of the wire and directing the electricity through a test circuit.
2. Description of the Prior Art
In many situations, a person testing or repairing electrical equipment must determine if electricity is flowing through a specific wire. Often the ends of the wire are unaccessible. As a result, a person must invasively test for the flow of electricity by piercing the insulation on the wire. In the prior art, there are many different types of circuit testing devices that are specifically designed to pierce the insulation on a wire and test for the flow of electricity through that wire. One such prior art device is the open end probe. Open end probes are probes that terminate at one end with a sharp implement. The implement is designed to pierce the insulation around a wire and contact the conductive core of the wire. The problem associated with open end probes is that there is nothing that holds the wire in place as the implement at the end of the probe is attempting to pierce the insulation around a wire. As a result, open end probes often slip and damage the insulation surrounding a wire without contacting the conducive core in the center of the wire. If a person is using his/her hand to hold a wire in place, a slipping open end probe presents a physical danger to that person because the probe can easily pierce the skin.
To eliminate the disadvantages of open end probes, hook end probes have been developed in the prior art. Hook end probes contain a hook structure opposite the piercing probe. A wire to be tested is placed in between the hook structure and the piercing probe. The hook structure holds the wire in place as the piercing probe advances against the wire. As a result, the piercing probe properly contacts the wire and the dangers of a slipping probe are eliminated. The problem with hook end test probes is that such test probes typically contain set springs. The set springs determine how hard the piercing probe is driven against a wire placed into the hook end probe. Wire comes in many different shapes and types. If a piercing probe is pressed too hard against a wire, the probe may sever the conductive core in the center of that wire. If the piercing probe is not pressed hard enough against a wire, the probe may not fully pierce that wire""s insulation. As a result, a probe with a set spring bias is incapable of working properly on all types of wires.
In many situations, a person using a test probe is testing a single wire located in a much larger bundle of wires. When a problem wire is detected, that person typically must remove the test probe and retrieve tools needed to repair the detected problem. Often during this process, the problem wire becomes lost within the larger bundle or the problem point on the suspect wire becomes lost as the repair worker directs his/her attention to finding tools. In the prior art, devices have been developed that help isolate a single wire in a bundle. However, plier-based circuit testers need room for the jaws of the circuit tester to open. In very confined areas, pliers cannot be used and a probe-based circuit tester is necessitated.
From the above, it can be seen that both plier based circuit testers and probe based circuit testers have both their own advantages and disadvantages. A need therefore exists in the art for a test probe that embodies the advantages of both a plier-based circuit tester and a probe-based circuit tester. This need is met by the present invention as described and claimed below.
The present invention is a tool for diagnosing and repairing defective wires. The tool is configured as a pair of pliers, wherein the pliers have the ability to cut, strip and twist wire. The pliers also contain two different piercing probes. One piecing probe extends from the body of the pliers, thereby enabling the pliers to be used as an open end circuit testing probe. The second piercing probe is located at a specific point on the jaws of the pliers. When a wire is placed in the jaws of the pliers at that point, the wire becomes pierced by the second piercing probe as the plier jaws close. The force at which the second piercing probe is biased against the wire is determined by the degree of manual force applied to the handles of the pliers.
As either of the piercing probes pierce the insulation surrounding a wire, the body of the pliers is brought to the same electrical potential as the wire. A wire lead extends from the pliers and connects to a ground potential at a remote location. The pliers contain a current flow indicator that is capable of providing a perceivable indication as to the flow of current though the pliers. If the indicator indicates that there is a flow of current, then the wire being tested is known to be functional. However, if a point in a wire is detected where the flow of current stops, the wire is known to be defective and the pliers can be used to cut, strip and recombine the wire in making the needed repair.